Keyframe side pin guide for piano and like musical instruments

ABSTRACT

There is described an improved keyframe side pin guide for pianos and the like musical instruments wherein means are provided for preventing warp curving of the front part or front rail of the keyframe and for holding the same constantly in closely contacting relationship with the key bed on which the keyframe is supported, the means comprising a pin projecting from the keyframe, a pin-receiving member having a verticallyextending slot therein, the pin being inserted in the slot, a guide piece slidable along the slot and resting on the pin, and a resilient member exerting a constant downward pressure on the guide piece, so that the pin is firmly pressed toward the key bed owing to the downward biasing force of the resilient member.

[ 1 Sept. 5, 1972 [$4] I KEYFRAME SIDE PIN GUIDE FOR PIANO AND LIKEMUSICAL INSTRUMENTS [72] Inventor: Eiji llarada, 1522-1 Kobayashi,Shizrioka-ken, l-lamakita-shi, Japan 221 Filed: May 14,1971 21 Appl.No.:143,425

[30] Foreign Application Priority Data Aug. 28, 1970 Japan ..45/85228 s2U.S. c1 ...84/432 51 1111.01. ..G1o3/12 [58] FieldofSearch ..84/423, 432

[56] r v References Cited I UNITED STATES PATENTS 480,014 8/1892 Hawes.;..84/432 745,509 12/1903 Muller; ..84/432 3,363,499 1/1968 Matsumoto.;...84/432 Primary ExaminerStephen J. Tomsky AssistantExaminer-Lawrence R. Franklin Attorney-Curt M. Avery et al.

[57] ABSTRACT There is described an improved keyframe side pin guide forpianos and the like musical instruments wherein means are provided forpreventing warp curving of the front part or front rail of the keyframeand for holding the same constantly in closely contacting relationshipwith the key bed on which the keyframe is supported, the meanscomprising a pin projecting from the keyframe, a pin-receiving memberhaving a vertically-extending slot therein, the pin being inserted inthe slot, a guide piece slidable along the slot-and resting on thepin,and a resilient member exerting a constant downward pressure on theguide piece, so that the pin is firmly pressed toward the key bed owingto the downward biasing force of the resilient member.

"9Claims,5DrawingFigures mimtb ir m I 3.688.634

sum 1 or 2 FIG. 7

R/OR ART KEYFRAME SIDE PIN GUIDE FOR PIANO AND LIKE MUSICAL INSTRUMENTSThis invention relates topianos and like musical instruments and moreparticularly to improved keyframe the keyframe causes differences orirregularities in the touches of the individual keys and noises areproduced when the keys are depressed by the player if there is a spaceor gap wider than 0.1 mm between the keyframe and key bed.

In order to prevent warp curving of the keyframe and to maintain thesame in closely contacting relationship with the key bed, there has beenproposed a keyframe side pin guidecomprising a pin projecting from thekeyframe, a pin-receiving member having a vertical slot therein, the pinbeing inserted in the slot, a guide piece slidable along the slot andresting on the pin, and adjusting screw means threadedly attached to thepinreceiving member, the screw means being permitted of the up and downmovement along the slot by being turned, the downward movement of thescrew means guiding the guide piece downward along the slot, therebypressing the pin of the keyframe toward the key bed and preventingupward curving of the front member of the keyframe.

The above prior keyframe side pin guide construction is effective to acertain degree in holding the keyframe firmly. Nevertheless, the priorconstruction using an adjusting screw has a drawback in that it requireselaborate adjustments from time to time to ensure that the keyframe isin correct position with respect to the key bed, and it is often founddifficult to make fine adjustment of the gap between the keyframe andthe key bed due to the fact that there is a limit to narrowing the pitchof the adjusting screw for such purposes.

It is therefore the primary object of the invention to provide animproved keyframe side pin guide which will eliminate the difficultiesmentioned above.

It is another object of the invention to provide keyframe side pin guidewhich is capable of constantly maintaining the keyframe infinitesimallyclose to the key bed without requiring any subsequent adjustment.

It is a further object of the invention to provide a keyframe side pinguide incorporating a resilient means for pressing a guide piece againstthe side pin of the keyframe.

It is still another object of the invention to provide a combination ofa leaf spring and a pressure transmitting member adapted to maintain thekeyframe constantly in closely contacting relationship with the key bed.

According to one feature of the invention, there is provided a keyframeside pin guide for a piano or like musical instruments connecting akeyframe to a key block, the guide comprising a pin projecting from thekeyframe, a pin-receiving member having a vertical slot therein, the pinbeing inserted in the slot, a guide piece slidable along the slot andresting on the pin, and resilient means exerting a constant downwardpressure on the guide piece, so that the guide pin is pressed to the pinowing to the downward pressure of the resilient means.

The foregoing and other objects and additional advantages as well asfeatures of the invention will be more fully understood from the ensuingdescription of the accompanying drawings, the latter serving forexplanatory purposes only and are not intended to in any extent limitthis invention and in which drawings:

FIG. 1 is a perspective view showing one example of the keyframe and keyblocks of a grand concert piano;

FIG. 2 is a fragmentary perspective view on enlarged scale of thekeyframe side pin guide of the known construction;

FIG. 3 is an elevational front view of the keyframe side pin guide shownin FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing a keyframe side pin guideembodying the invention; and

FIG. 5 is an elevational front view of the keyframe side pin guide shownin FIG. 4.

Referring to the accompanying drawings, FIG. 1 shows an example of acombination of the keyframe and key blocks each located at the side ofthe keyframe. The keyframe l is formed by assemblage of afront rail 6, abalance or intermediate rail lb, a back or rear rail la, and a pluralityof transverse slats 10 connecting the rails. The keyframe l is freelymovable horizontally in the longitudinal direction over a key bed (notshown) under the guidance of back rail guides 2. A keyframe side pinguide 5 is mounted by means of wood screws 8e onto an inner end face ofeach key block 3 or 4 for engagement with outwardly extending side pins7 which are partly embedded fixedly in the bass and treble ends of thefront part or front rail 6 of the keyframe.

As shown in FIGS. 2 and 3, it has been the conventional practice toprovide a side pin guide body 8 generally of a saddle shape. The guidebody is provided with two wing-like side portions 8b joined by an uppercross piece or bridge 80, an adjusting screw 10 in screw threadengagement with a vertical tapped through hole formed in the bridgemember, and a guide piece 9 slidably engaged in a vertical cutout slot8a formed in the guide body 8 at a position below the bridge member 8cand between the inner sides of the flanged portions. The wing portions8b are respectively provided with a horizontally elongated slot 8d formounting the guide body 8 onto the key block 3 or 4.

The adjusting screw 10 is inserted from the upper side of the bridge insuch a manner that the lower tip of the screw rests'against the uppersurface of the guide piece 9.

The key blocks 3 and 4 located respectively at the bass and treble endsof the keyframe l are secured to the key bed (not shown). Each side pinguide assembly 5 is mounted on its respective key block by means of woodscrews See, the screws being passed through the slots 8d formed in theguide body and screwed into the key blocks 3 and 4 as shown in FIG. 2.The surface of the key block is recessed for receipt thereinto of thepin guide assembly 5 so that, when the side pin guide is mounted, itsouter most part does not project outward beyond the inner end face ofthe key block. The key block is further forrned'with a groove or cutout3a above the adjusting screw so that a screwdriver can be inserted fromabove to turn the adjusting screw.

With the above described prior keyframe side pin guide construction, theside pin may be closely held by the guide piece and the keyframe frontrail may also be prevented from curving upward. However, in order toensure that the keyframe be held constantly in optimum position withrespect to the key bed, the adjusting screw must be loosened ortightened from time to time by elaborately inserting a tip of ascrewdriver through the narrow gap or space provided by the eutoutgroove and, therefore, the adjusting operation is sometimes renderedannoying and difficult.

The present invention contemplates to provide a new and improvedkeyframe side pin guide construction whereby the keyframe front rail maybe prevented from beingcurved due to warping by means of a resilientmeans adapted to depress the guide piece firmly against the side pin,without requiring any additional or subsequent adjustment once the sidepin is held in position.

Referring to FIGS. 4 and 5, there is shown a keyframe side pin guideconstruction according to the present invention. The side pin guide ofthe invention comprises a pin guide body or pin-receiving member 1 l ofgenerally symmetrical saddle shape and integral structure havingwing-shaped side portions 110 on opposite sides of a verticallyextending cutout slot 11a. The wing portions 11 are bridged by acrossing or bridging member 11d and formed with horizontally extendingelongated slots 11b. These elongated slots 11b are adapted to receivetherethrough wood screws 13 for fixedly mounting the guide body orpin-receiving member 11 onto the key block 3. A guide piece 12 is fittedin the cutout slot 1 la so as to be vertically slidable therein.

Formed vertically through 'the bridge or crossing member 11d is athrough hole lle for receiving therethrough a lower or larger diameterportion 140 of a pressure transmitting rod member 14. The rod member 14is provided with a smaller diameter portion 14b at its upper end. Therod member 14 is inserted from above into the vertical through hole lleof the bridge member 1 1d with its lower tip end rested against theupper surface of the guide piece 12. The guide piece 12 is placed on thepin 7 so as to press the pin 7 downward.

Disposed above the guide body 11 a resilient means which, in theexample, is shown as an elongated leaf spring member 15 adapted todepress the guide piece 12 firmly against the side pin member 7 by wayof the pressure transmitting rod member 14. One end of the leaf springmember 15 is fixedly secured to the key block 3 while the other end isrested against a stepped portion or shoulder 140 of the rod member 14,so that it exerts a downward biasing force on the rod member 14. Thesmaller diameter portion 14b of the rod member 14 is passed through ahole formed in the leaf spring member 15 adjacent to the free endthereof. As for a resilient means, the leaf spring member 15 ispreferred to have such pressure as to be capable of exerting from abovea depressing force of 3 to 5 kg/cm on the stepped portion or shoulder14c of the pressure transmitting rod member 14.

It will be appreciated that, with the side pin guide construction of theinvention described above, the side pin 7 embedded in each of the bassand treble ends of the keyframe may be constantly firmly held inposition by means of cooperating action of the leaf spring 15 and guidepiece 12 receiving a downward pressure therefrom through the pressuretransmitting rod member 14. Accordingly, the keyframe front rail 6 isprevented from warp curving and the gap between the front rail 6 and thekey bed may at all times be maintained narrower than 0.1 mm once theside pin is fitted into the side pin guide without such subsequentadjustments as heretofore been required in the prior art side pin guideconstruction.

It will be understood that a side pin guide of the same construction ismounted symmetrically onto each one of the key blocks locatedrespectively at the bass and treble ends of the keyframe, although theforegoing description has been made in conjunction with only one sidepin guide construction. a

While a specific embodiment of an improved side pin guide for pianokeyframes has been disclosed in the foregoing description, it will beunderstood that various modifications and changes within the spirit ofthe invention may occur to those skilled in the art. For example, thepressure transmitting rod member maybe of a construction other thandescribed hereinbefore and illustrated in FIG. 4 and 5 insofar as it iscapable of transmitting the downward biasing force of the leaf springfrom above to the guide piece urging the side pin of the keyframe in adownward direction. Therefore, it is intended that no limitations beplaced on the invention except as defined by the scope of the appendedclaims.

What is claimed is:

l. A keyframe side pin guide for piano or like musical instrumentsconnecting a keyframe to a key block, said guide comprising a pinprojecting from said keyframe, a pin-receiving member having a verticalslot therein, said pin being inserted in said slot, a guide pieceslidable along said slot and resting on said pin, and resilient meansexerting a constant downward pressure on said guide piece, so that saidguide pin is pressed to said pin owing to the downward pressure of saidresilient means.

2. The guide as claimed in claim 1 wherein said resilient means is aleaf spring.

3. The guide as claimed in claim 1 wherein said pinreceiving memberincludes a pair of side portions and a bridge portion coupling said sideportions, said portions defining said vertical slot therebetween, saidpressure transmitting member being slidable through a through holeformed in said bridge portion.

4. The guide as claimed in claim 1 further comprising a pressuretransmitting member interposed between said resilient means and guidepiece, said pressure transmitting member transmitting said downwardpressure of said resilient means to said guide piece.

5. The guide as claimed in claim 4 wherein said pinreceiving member hasa through hole perforated therein, and said pressure transmitting memberis inserted in said through hole so as to be slidable therethrough.

6. The guide as claimed in claim 4 wherein said pressure transmittingmember has a larger diameter portion, a smaller diameter portion, and astepped pressure on said guide piece, so that said guide pin is pressedto said pin owing to the downward pressure of said resilient 'means. a

8. The guides as claimed in claim 7' wherein said resilient means is aleaf spring.

9. The guides as claimed in claim 7 further comprising a pressuretransmitting member interposed between said resilient means and guidepiece, said pressure transmitting member transmitting said downwardpressure of said resilient means to said guide piece.

$ 2353? 32 x212 OFFICE r-v, r \1 :2 QER Iii iKCA-LTE QQERFMGTAUBT PatentN 3, 88,63 Dated September 5, 1972 Iw nt fls) EIJI HARADA in theabove-identified patem:

It is cert Eied that error 2133;; s

1 e y corrected as shown below;

and that said Letters Patent are n f In the heading to the printedspecificat'ioh there should be included:

----Ass:tgn -2e: Nippon Gakki Sei'zo Kabushiki Kaisha Hamamatsu-shi,Japan Signed and sealed izhie 26th day of March 1972 (SEAL) Attest: I

A EDWARD M.FLETCHER JR. C MARSIiALL DANN Attesting OfficerCommissionerof Patents 2 7 3 STE-LL35 iAiE T OFFICE @F QCQRLBCTEOXPatent No.- 3 688,63 4 Dated September 5, 1972 IWenT- M EIJ I HARADA Itis certified that-error appears 1;. the above-ider ltified patent andthat said Letters Patent are hereby corrected as shown. below:

In the heading to the; printed specificatioh there should be included:

-Assignee: Nippon Gakki Seizo Kabushiki Kaisha Hamamatsu-shi, JapanSigned and sealed this 26th day of March 197% (SEAL) Attest: I

EDWARD M.FLETCHER,JR. C. MARSIPXLL DANN Attesting Officer Commisslonerof Patents

1. A keyframe side pin guide for piano or like musical instrumentsconnecting a keyframe to a key block, said guide comprising a pinprojecting from said keyframe, a pin-receiving member having a verticalslot therein, said pin being inserted in said slot, a guide pieceslidable along said slot and resting on said pin, and resilient meansexerting a constant downward pressure on said guide piece, so that saidguide pin is pressed to said pin owing to the downward pressure of saidresilient means.
 2. The guide as claimed in claim 1 wherein saidresilient means is a leaf spring.
 3. The guide as claimed in claim 1wherein said pin-receiving member includes a pair of side portions and abridge portion coupling said side portions, said portions defining saidvertical slot therebetween, said pressure transmitting member beingslidable through a through hole formed in said bridge portion.
 4. Theguide as claimed in claim 1 further comprising a pressure transmittingmember interposed between said resilient means and guide piece, saidpressure transmitting member transmitting said downward pressure of saidresilient means to said guide piece.
 5. The guide as claimed in claim 4wherein said pin-receiving member has a through hole perforated therein,and said pressure transmitting member is inserted in said through holeso as to be slidable therethrough.
 6. The guide as claimed in claim 4wherein said pressure transmitting member has a larger diameter portion,a smaller diameter portion, and a stepped shoulder portion at which saidlarger and smaller diameter portions join, said resilient means beingmounted on said stepped shoulder portion.
 7. A pair of keyframe side pinguides for piano or like musical instruments connecting a keyframe to apair of key blocks each disposed at the sides of said keyframe, each ofsaid guides comprising a pin projecting from said keyframe, apin-receiving member having a vertical slot therein, said pin beinginserted in said slot, a guide piece slidable along said slot andresting on said pin, and resilient means exerting a constant downwardpressure on said guide piece, so that said guide pin is pressed to saidpin owing to the downward pressure of said resilient means.
 8. Theguides as claimed in claim 7 wherein said resilient means is a leafspring.
 9. The guides as claimed in claim 7 further comprising apressure transmitting member interposed between said resilient means andguide piece, said pressure transmitting member transmitting saiddownward pressure of said resilient means to said guide piece.